1. Field of the Invention
The present invention relates terminating an optical fiber of a cable, and in one aspect to a device for terminating an optical fiber and adapting it to be readily connected to another fiber, i.e. a distribution fiber.
2. Description of the Prior Art
The prior art has a variety of connector and splice structures for affording the connection of an end of one optical fiber to the end of another optical fiber for the purpose of joining the two suitably to continue the light through the fibers. The splice is a device which can be applied by a skilled technician in the field who cleaves the fiber, abuts two fiber ends and joins them permanently together by a splice. The connector comprises a connector plug, coupling and connector plug to form the continuation for the light and each connector plug has the end of a length of optical fiber carefully aligned in and secured to the plug in an assembly plant or as a field operation requiring special equipment and great care to terminate the fiber precisely. This plug and fiber end may then be readily connected to the end of another fiber which is joined to a connector plug in a connector coupling by almost anyone with minimal assembly skills. The technicians then are the workers with the responsibility of taking the optical fiber cable that has arrived at the communications station and then take the individual optical fibers and splice each of them to fibers leading from connector plugs such that they can be subsequently connected to the connector plug of a fiber running to an opto-electronic piece of equipment. When this piece of equipment is a piece of equipment in the home, factory or office work station and the number of optical fibers directed thereto are all contained in a single cable, or the cable contains optical fibers together with copper signal wires, it is desirable to have a convenient means of termination of the optical fibers as well as a convenient method of joining the copper wire to a distribution wire. This termination should not require any more skill than the technician that would routinely service and install such cables. If it requires tools that cut and polish the optical fiber end and special fixtures to secure the finished fiber end in a plug, then the level of skill required to make only several connections at remote locations is not economically prudent commercially, and the optical fiber distribution system will not grow and be as readily available to as many citizens as rapidly as desired. Presently, where large installations are made in a building or central station, a distribution housing is installed and the cable is brought in for distribution. Individual optical fibers from the cable are spliced to long pigtails, each consisting of individually jacketed optical fiber terminated into a connector plug at one end. The pigtail connector plug is mounted into a connector coupling located within the distribution housing or a remote second distribution housing. The splice joining the two fibers is placed within a splice holder within the first distribution housing. The surplus fiber from the pigtail and surplus fiber from the cable are both carefully stored in the distribution housing. A second plug mates with the first in the connector coupling and routes to an opto-electronic device or other intermediate junction. This is the routine which must be followed to allow slack for removal of the fiber from the distribution housing for application of a plug, either as a precise field cut and polish operation or through splicing of a factory made plug with a fiber pigtail.
A prior device, identified as an optical cable header is described in U.S. Pat. No. 4,585,303, utilizes a plurality of optical connector supports which are engaged in a magazine or housing. The connector supports have an elongate body in the form of a hollow finger. The finger has a cylindrical connector member at a front end, to receive the connection end fitting on the end of each incoming fiber, and a side mounted former, upon which to wind a length of fiber, is located near to its opposite or rear end. The magazine has a row of cavities which are open at the rear of the magazine for receiving the supports. The cavities have circular openings in the front wall to receive the connector members of the connector supports when they are received in the cavities. The optical connector will also receive an analogous end fitting of an external fiber for connection to the fiber inside the finger. The connector described in the introduction is an installed connection end fitting, for example the one described in French Pat. No. 2 275 787 and in its certificate of addition 2 316 611, the earliest patent corresponding generally to U.S. Pat. Nos. 3,989,567 and 4,050,783. The connector described in these patents is designed to receive one or multiple fibers, but to receive one fiber, requires an installation and in each end fitting, the end face of a fiber is rectified and suitably positioned for providing accurate optical connection when two connection fittings are brought together. The installation of the end fitting is not perceived as a field installation since Pat. No. 4,585,303 refers to the cable having a plurality of optical fibers with each fiber having a connection end fitting installed on its end. The purpose of the patented header is to avoid having to interrupt the connection of several fibers as with the connector of Pat. No. 4,050,783, when repairing a defect in the connection between any one pair of fibers.
The purpose of the present invention is to provide a module which allows splicing of a fiber to a connector plug pigtail within the module, thus eliminating the need for excess slack between the splice and plug, and between the splice and the balance of the feeder system as formerly required to remove the splice to a location suitable for the precise operation required.
Reliable mechanical splices of several designs have recently become available which make this splicing within the module possible.
It is therefore an object of this invention to provide a termination which will reduce the need for large or bulky boxes to handle incoming and distribution fibers and afford the installation of only one or a few optical fibers as needed, such as a small service tap into a residence, apartment or office or factory work station for connection of those optical fibers to opto-electronic equipment.
The module of the present invention should be easy to use to make the termination with incoming, unterminated fibers, so they are readily accessible to make connection with companion plugs on distribution cables.